.header,
.video,
#page-main {
  width: 100%;
}
.header img,
.video img,
#page-main img {
  width: 100%;
}
.header video,
.video video,
#page-main video {
  width: 100%;
}
.header {
  position: relative;
}
.header .qr-code {
  width: 25%;
  position: absolute;
  bottom: 4%;
  left: 50%;
  transform: translateX(-50%);
}
